Date: Sun, 30 May 2021 20:49:32 -0700 From: Mark Millard via freebsd-arm <freebsd-arm@freebsd.org> To: freebsd@dsllsn.net Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Boot from USB on RPi4 8GB? Message-ID: <AE68DF43-94AF-4293-82CF-7325D57E3BB7@yahoo.com> In-Reply-To: <FA5F90A1-0E02-4CC8-A860-38C62E0ED93E@dsllsn.net> References: <4F3EE8D2-649B-4522-AD5A-7C308291802F@dsllsn.net> <43FAEEAC-EE36-4810-88AA-FF82AFBCC128@yahoo.com> <2F58272B-BD9C-464B-9A98-BF638971BA86@dsllsn.net> <D82CA5FE-1755-4D38-928E-B8234A4F38D4@yahoo.com> <E267DA59-F294-40D4-B2DB-4E6DF8C87DCF@yahoo.com> <FA5F90A1-0E02-4CC8-A860-38C62E0ED93E@dsllsn.net>
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On 2021-May-30, at 16:54, William Carson via freebsd-arm <freebsd-arm at = freebsd.org> wrote: >> On May 30, 2021, at 4:08 PM, Mark Millard <marklmi@yahoo.com> wrote: >>=20 >> On 2021-May-30, at 13:50, Mark Millard via freebsd-arm <freebsd-arm = at freebsd.org> wrote: >>=20 >>> On 2021-May-30, at 10:59, William Carson via freebsd-arm = <freebsd-arm at freebsd.org> wrote: >>>=20 >>>>> . . . >>>>> I use a USB3 SSD that has small enough power requirements >>>>> to not require a powered hub. (I also use a 5.1V 3.5A >>>>> power supply as part of that context.) I've never tried >>>>> spinning rust or higher powered USB3 media. >>>=20 >>> I view the power supply that I use as just giving a little >>> more margin, not as a way to increase what the devices >>> total to. >>>=20 >>>> . . . I'm not sure what's considered "high powered" but the Samsung = tech specs say this particular model uses 5.7 W on average and 10.0 W = maximum. But it does seem curious that the Raspberry PI OS will boot = this disk without issue, so I don't think it's the drive. I also tried a = Samsung 950 PRO using a different enclosure (QNINE NVME Enclosure, M.2 = PCIe SSD (M Key) to USB 3.0 External Case), but it behaved the same. >>> . . . >>>=20 >>> Then you need to use a powered hub for that device. >>=20 >> I should have just referred to independent power. You >> had written: >>=20 >> QUOTE >> I'm trying to use a SAMSUNG (MZ-V7E500BW) 970 EVO SSD 500GB - M.2 = NVMe, attached via the Geekworm X872 M.2 NVMe 2280/2260/2242/2230 SSD = Expansion Board. >> END QUOTE >>=20 >> = https://geekworm.com/products/raspberry-pi-4-x872-m-2-nvme-2280-2260-2242-= 2230-ssd-expansion-board >>=20 >> shows that it has its own power connector and has an image >> that says "please power x872 via DC Jack of XH2.54 connector >> if SSD is not recognized or low power". Later text on the >> page says: >>=20 >> QUOTE >> Specifications: >> Power Supply >> =E2=80=A2 5Vdc +/-5% , Powered by Raspberry Pi USB port >> =E2=80=A2 5Vdc via DC power jack or XH2.5 connector, Extra power = for the SSD >> END QUOTE >>=20 >> So, if I gather right, you need to connect a power >> supply to the X872 and another to the RPi4B. >>=20 >> Another image says "Note: NOT recommended to use SAMSUNG SSD, >> if use SAMSUNG SSD, please close WiFi". Later text on the page >> says the same. >=20 > A-ha, indeed. I just noticed that as well. I've gone ahead and ordered = a supplementary power supply and a lower-power NVMe to do more testing. = I'll send an update once I've received and tested them. >=20 > Thank you for hopefully pointing me in the right direction. I do not know if the "supplementary power supply" would be sufficient for the existing drive to work, but it is likely necessary. Similarly for any other drive that could require a significant portion of the 1.2A at times. (I've no clue what else you have plugged into USB or how much power(/current) those devices take (if any). So I do not know what to subtract from the 1.2A.) The USB3 SSDs that I'm using are based on: ATA Version is: ATA8-ACS, ACS-2 T13/2015-D revision 3 SATA Version is: SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s) This helps explain why I've got no power problem: older technology. Note that SATA 3.0 can be somewhat faster than the original USB3 already, at least in some respects. >> = https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/READM= E.md >>> lists: >>>=20 >>> "Maximum total USB peripheral current draw" as: 1.2A , >>> which at 5.1V is 6W. (Possibly should have listed the 6.12W figure.) >>> That figure is the total for all USB devices attached >>> that are not powered independently. >>>=20 >>> That document also says that a 5.1V supply is required, >>> not 5V. >>>=20 >>> The power supply that the RPi folks supply is 5.1V @ 3A >>> or 15.3W. Even the 5.1V 3.5A power supply that I use >>> only multiplies out to 17.85W. >>=20 >=20 >=20 =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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